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United States Patent 3,139,663 CONCRETE CASTING MACHINE Joseph I.Boswell, Vicksburg, and Tiiden Burke, Greenville, Miss., George F.Dixon, Jr., Carlisle, Pa., and Goode S. Lee, Warren County, Miss.,assignors to the United States of America as represented by theSecretary of the Army Filed Sept. 29, 1961, Ser. No. 141,914

6 Claims. (Cl. 25-2) (Granted under Title 35, U.S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without the payment of anyroyalty thereon.

The present invention relates to improvements in automatic apparatus forcasting, on a production line basis, articulated concrete revetment matsemployed to protect river banks and flood control levees from hydraulicerosion.

In particular, the present invention relates to improvements in castingplants of the type described in U.S. Patent No. 2,835,016, entitledConcrete Casting Machine, issued to George F. Dixon, l r., on May 20,1958. Although concrete castings of virtually any shape could beproduced in accordance with the present invention, the castings to beformed by the embodiment herein described in detail are of thestandardized size and construction used by the U.S. Army Corps ofEngineers in connection with flood control projects on the MississippiRiver. The articulated mat castings are described in detail in theabove-mentioned patent. Each casting is approximately four feet Wide,twenty-live feet long and three inches thick. Each casting coversapproximately one-hundred square feet installed and is commonly referredto as a square Each articulated square is comprised of twenty concreteslabs approximately one foot Wide extending transversely of the castingand interconnected by a continuous Wire fabric embedded in the concreteat a plane about the midpoint of the thickness of each slab. Wheninstalled, the squares are connected end to end and side to side to forma continuous flexible mat of any desired size.

While the above-cited patent discloses the general concept of a machinefor producing cured concrete castings on a production line basis Withina building to provide all- Weather operation by mechanical forming meansusing vibration compacting and low Water-cement ratios with acceleratedcuring in a kiln, the embodiment therein described has proveninefficient and therefore uneconomical to operate. This inefficiency isprimarily caused by a low production rate due at least in part to thefact that the described apparatus required manual instigation of each ofthe various mechanical movements, with the conveyor system being stoppedduring each forming operation.

Therefore, the object of the present invention is to provide asubstantially automatic casting apparatus of the type described havingan increased output and therefore greater economy of operation.

Many additional objects and novel features of construction whichdirectly contribute to an eicient and economic apparatus and theadvantages which result therefrom Will be obvious from a reading of thefollowing detailed description in which:

FIGS. la, lb and lc, taken together, show a plan layout of a concretecasting plant constructed in accordance with the present invention;

FIG. 2 is a side elevation of a chain sprocket and asociated structurelocated at the slack take-up works shown in FIG. lc;

FIG. 2a is a detailed plan vieW of an expansible rail joint shown inFIG. 2;

FIG. 2b is a detailed side elevation of the eXpansible rail joint ofFIG. 2a; Y

ice

FIG. 3 is a sectional elevation taken on line 3-3 bf FIG. 2;

FIGS. 4a, 4b and 4c are schematic illustrations of the operation of thecasting forming station of the plant shown in FIG. la;

FIG. 5 is a time and sequence chart for the'casting forming stationillustrated in FIGS. 4a, 4b and 4c;

FIG. 6 is a schematic illustration of the motion of a part of thecasting station during operation;

FIG. 7 is a detailed diagrammatic elevational view, partly in section,of the casting station for the plant shown in FIGS. la, lb and 1c;

FIG. 8 is a detailed diagrammatic, transverse elevational view of thecasting station, shown partly in section, taken on line 8 8 of FIG. 7;

FIG. 9 is Ian enlarged view showing details of construction, partly insection, of the nesting guides hereafter described in detail;

FIG. 10 is an enlarged view of the casting station as viewed from theleft end of FIG. 8 showing details of construction, partly in section;

FIG. 1l is a top view of a portion of the casting forming station of theplant shown in FIG. 7;

FIG. 12 is an enlarged longitudinal sectional view showing details ofconstruction of the casting forming station; l

FIG. 12a is a detailed top view of a part of a conveyor chain shown inFIG. 12;

FIG. 13 is a schematic diagram of the hydraulic system for actuating thevarious working elements of the casting forming station of the plantshown in FIG. 7;

FIGS. 14a and l4b, taken together, comprise a Wiring diagram of theelectrical system for controlling the sequential operation of thehydraulic system shown in FIG. 13 and hence the operation of thecastingY forming station;

FIG. 15 is a plan View of a device for engaging and removing curedconcrete castings from the conveyor system of the casting plant; H

FIG. 16 is a side elevation of the device of FIG. 15;

FIG. 17 is a sectional end elevation taken on line 17-17 of FIG. 15 witha concrete mat in phantom outline;

FIG. 18 is a diagrammatic perspective of the concrete casting removalstation; i

FIG. 19 is a detailed horizontal cross section of the cradle lifterguide shown generally in FIGS. 7 and 8; and

FIG. 20 is a detailed sectional view taken on line 20-20 of FIG. 19. ,A

In accordance with the present invention, a continuously moving conveyorsystem transports a large number of flat pallets successively to aforming or casting station Where a concrete casting is formed on eachpallet. The pallets are then transported through a curing kiln Where arelatively high temperature and maximum humidity is maintained, to acasting removal station where a novel hoist removes the cured castingsfrom the pallets, past a pallet cleaning brush Which removes concretefragments which may remain on the pallets, to a station where twooperators manually position a Wire fabric on the pallets, past an oilingstation where oil is dripped onto the pallets to prevent the concretefrom sticking to the pallets, and once again to the forming station tocomplete the' cycle. The entire operation is continuous andsubstantially automatic in that it requires only an operator for theconventional concrete mixing plant which supplies the forming stationwith plastic concrete, an operator stationed at the forming station tosupervise and act in the event of a malfunction of the plant, anoperator for the casting removal hoist, and two operators forpositioning the Wire fabric on the pallets.

FIGS. 1a, 1b and 1c taken together show a plan viev`v` of a plant layoutin accordance with the present invention.

aisaeea A suitable building indicated generally by 300 is ofconventional design using vertical I beam columns 301 supported by aconcrete foundation 302 and with siding 303 attached thereto. Thebuilding is divided into two general compartments, the rst being thatshown in FIG. la which houses the casting forming and the removal stagesof the operation, and the second shown in FIGS. 1b and y 1c whichcomprises a curing kiln.

The kiln begins at the partition 300:1 which has two openings therein toreceive a conveyor system and includes all of the building structureshown in FIGS. lb and 1c. The kiln is properly insulated in a suitablemanner so thatthe area can economically be maintained at a hightemperature by five heating units with blowers, located generally at30017. A steam generator is also provided at 300e` to maintain thehumidity within the kiln as high as practicable. The heaters, steamgenerator and kiln building structure can be of any conventional type asthe details of these components are not critical to the presentinvention. In an actual embodiment, the kiln is maintained at V180 F. atthe entrance and 210 F. at the take-up works lwith a humidity ofapproximately 90 percent.

A concrete mixing plant of conventional design is shown generally at 305and provides a volume of plastic concrete as demanded by the castingoperation. The actual embodiment has four 50Vcubic feet capacity batchmixers capable of mixing 37 cubic feet every every four minutes, andsuitable concrete and sand silos and a water tank.

An endless conveyor system for transporting the flat Vpallets upon whichconcrete castings are formed extends substantially the entire lengthofthe building 300 and has an upper reach which travels from the part ofthe building shown in FIG. 1a into the kiln and a lower reach directlythereunder which travels in the opposite direction. By

using this system, the freshly formed castings carried by the systemtravel'twice the length of the kiln to provide ya longer curing time.

The conveyor system has two endless chains 336 and 307. The two chainsare of the same link construction. Each link is comprised of a pair ofparallel plates 308 which are interconnected by a pair of bradded bolts308e which pass through spacer bushings 308b as shown in FIG. 12a. Thesuccessive links are pivotally connected at adjacent ends by pins 309. Aroller 310 is journalled on cach pin 309. The rollers travel on chaintracks 311 which support the weight of the chains along both the upperand lower reaches. A side plate 312 extends along the outside of eachchain track to maintain the chain on the track.

Synchronous movement of the two chains is provided by four separateelectric driving mechanisms, each being of substantially identicalconstruction. Two of the drives are in superimposed relation so thatonly one can be seen in FIG. la, generally at 332. One drives the upperreach of the conveyor system and the other drives the lower reach.Similarly, two drives are shown in superimposed relation in FIG. 1bgenerally at 383 with one driving the upper. reach and the other thelower reach of the conveyor system.

Now, describing one of the four drive systems, reference is made toFIGS. la, 1b, 12a, and 18 wherein an electric motor 331 drives a shaft380 by means of a chain and sprocket arrangement. At each end of theshaft 330, which extends transversely across the building, a chain 384drives a sprocket 385e on a shaft 386e which drives another sprocket387a which drives lug chains Sa having lugs which mesh between the twospacer bushings 308b of each chain link and thereby drive the chains.Since each of the drive mechanisms for the two parallel chains uses asingle motor with interconnected speed reduction gearing, the two chainsmust remain synchronized.

The ilelds of the four motors 381 which drive the reduction gearing areindividually controlled by rheostats which are manuallyadjusted in aconventional manner to disl tribute equally the load between the fourdrive motors so that chain slack is fed to the take-up sprockets.

The conveyor system also includes a large plurality of cradles indicatedgenerally at 365, each of which supports a pallet 460 upon which theconcrete castings are formed. Each cradle is suspended like a seat on aFerris Wheel from a pair of two-wheel dollies shown generally at 370 and372 in FIG. 8. As shown in FIG. 10, the cradle frame is formed of twoend plates 367 which are interconnected by I-beams 366 to form an openrectangular structure. Axles 36S protrude horizontally from the endmembers 367 and are journaled in a rectangular chassis frame 369. A pairof wheels 370a are disposed within the chassis and rotate on axlesconnected within the chassis frame 369.

The dollies 370 and 372 travel on cradle dolly tracks 356 which arelocated between and slightly below the chain tracks 311. On the upperreaches of the conveyor system, the cradle dolly tracks are indicated at357 as in FIG. 7. The dollies, it will be noted, are so constructed asto operate in one position as the cradles are traversing the upper reachand in an inverted position as the cradles are traversing the lowerreach. v

Each of the two endless chains has a plurality of pairs of correspondinglugs 38S, best shown in FIGS. 10 and 12, spaced at uniform intervals ofabout four and one-half feet. The lugs on the chains are so arrangedthat two opposing lugs are always in alignment as the chains aresynchronously propelled by the driving means. Each dolly of each cradlehas an inverted angle iron arm 386 extending outwardly from the chassistoward the chains. A right triangular wedge-shaped plate 387 isvertically disposed and connected to the end of arm 386. The verticaledge of the wedge plate 337 is aligned with the center of the stub axle368 of the dolly. A pair of corresponding lugs 385 of the chain engagesthe vertical edges 388 of the two wedges 387 of a cradle and push thecradle along the cradle tracks.

As previously mentioned, each of the four turn around sprockets are ofidentical construction, with only the support structure for the varioussprockets being different. The sprocket illustrated in FIGS. 2 and 3 hasan axle 335 which extends outwardly from the conveyor system and isjournaled in two bearings 333 and 334 which are supported by suitableI-beam structure hereafter described. Each sprocket has an inner radialflange 338 and an outer radial flange 337 which are supported bysuitable spoke structure radiating from the axle. A plurality of teeth339 are equally spaced around the periphery of the outer radial ilangesso that generally U-shaped notches 371:1 in the outer ends thereof willreceive each roller of the chain as the chain passes around thesprocket. Teeth 371 are spaced around the inner radial flange to receivethe axles 3238 of the cradles. The notches 371a of the teeth 371 aretapered so that the cradles are set slightly ahead of the chain as thetwo pass around the sprocket to insure that the chain lugs do notinterfere with the cradle lugs and that the chain readily re-engages thecradles as they are released on the lower reach by the sprocket teeth- Acurved continuation of each cradle track is attached to each sprocketsupport structure. Referring specifically to FIGS. 2 and 3, for example,the cradle tracks 357 of the upper reach extend from a curved portion357:1 completely around the sprocket to straight portion 35717. Thiscurved continuation is supported by plates 358 and 358b positionedbetween the two sets of teeth on the sprocket which plates are supportedby structure 358e. The lower cradle track begins in a curved portion 373and curves around to a straight portion 356 which is the lower reach.

As the cradles are engaged by the sprocket teeth, the curvedcontinuation of the upper track 357 slowly turns the chassis frame fromthe horizontal. As the cradle approaches the horizontal position withthe sprocket axle, the dollies slide outwardly into engagement with thelower track extension 373 and are lowered at a constant rate` until theyare inverted and released on the lower reach 356 where they arere-engaged by the chain lugs and moved along the lower reach. Similarcurved tracks for the chains 306 and 307 are not required becausetension on the chain will keep the chains engaged with the sprocketteeth. Substantially the same operation occurs at the head-workssprockets, except of course the conveyor is moving the cradles from thelower reach to the upper reach.

Each of the four sprockets is associated with similar curved track andsupport structure as described heretofore. However, the supportstructure at the head-works, shown in FIGS. 1a and 18, is stationarywhile the takeup support structure located in the kiln, FIG. 1c, ishorizontally movable to provide a means for taking up slack in thechains due to thermal expansion. A generally rectangular floatingstructure bounded by members 328, 329 and 327 supports the trackcontinuations of both the upper and lower reaches. This rectangularstructure has lower beams 321 and 322 which ride on sets of rollers 317and 318, respectively, as shown in FIG. 3. The axles of rollers 317 areinterconnected by bars 319 and 319rz and the axles of rollers 318 aresimilarly interconnected by bars 320 and 320a. These roller sets travelon I-beams 309C and 310e', respectively, which rest on concretefoundation 303e. Transverse beams 315 support a third I-beam 316.Brackets 324 are connected to cross beams 323 of the riding structureand embrace and slide along beam 316 to maintain the riding sprocketstructure in proper alignment on rollers 317 and 318.

A cable 339:1 is connected to eyelet 340 of the riding structure andpasses outside the kiln to weight tower generally indicated at 341,shown in FIG. 1c. The cable passes under a sheave 342 and over a secondsheave 344 and supports a weight 345. The weight 345 continually exertsa force on the riding sprocket structure in such a manner as to keep thechains taut during thermal expansion and contraction. A similar take-upsprocket, riding support and weight tower therefor is provided for theother chain.

Each of the two chain tracks and each of the trolley tracks has anexpansible joint between the permanent structure 374 in both the upperand lower reaches to permit free movement of the take-up works and yetprovide a continuous uninterrupted track for the rollers. One type ofexpansible joint which has proven successful is shown in FIGS. 2a and2b. A plurality of flat plates 375 are turned on edge, separated byspacers 376 and are connected to the riding structure by pins 377. Asimilar set of ilat plates 378 are alternately disposed between plates375 within channel 330. Plates 378 are alternately separated by spacerplates 379 and are connected to stationary conveyor system supportstructure 374 by bolts 37451. Plates 375 slide relative to plates 378 asthe floating take-up structure moves and continually provide a leveltrack for the chain or cradle rollers as the case may be.

The conveyor system continuously transports the casting pallets in acomplete cycle, which for convenience of discussion can be considered asbeginning at the fabric station. As the pallets approach the fabricstation, they are clean and ready for the casting operation. A platform700 extends transversely of the conveyor system above the upper reach ofthe chain. A sliding access door 702 in building 300 provides a meanswhere a bail of preformed fabric units can be conveniently placed on theplatform by a suitable traversing hoist. Each preformed fabric elementis comprised of copper coated steel wire and has three parallellongitudinal links interconnected at spaced intervals by ten rectangularloops extending transversely thereof as can readily be seen at 704 inFIG. la. Each pallet is provided with three spring loaded, boomer-typesnatch latches at each end thereof which engage the ends of the longstrands of the fabric. Two operators manually place a fabric element oneach pallet as it emerges from under the platform.

The pallets with fabric latched thereon proceed under an oiling station706 where a small quantity of oil is dripped from a perforated tube ontothe surface of the pallets to prevent the concrete from stickingthereto. A suitable reservoir (not shown) feeds oil to the tube bygravity. Of course some oil will wet the fabric wires also, but sincethe wires are completely encased by concrete, this is unimportant, andoiling the pallets after the fabric station provides cleaner workingconditions for the fabric operators.

Next the pallets proceed to a casting station where a concrete square iscast on each pallet. The operation of the casting station isschematically illustrated in FIGS. 4a, 4b, and 4c taken in conjunctionwith time and sequence chart FIG. 5.

Referring specifically to FIG. 4a, the conveyor system is moving fromleft to right as indicated by the arrow. Cradle D, position V, has afreshly formed casting thereon and is being transported away fromthecasting station. Cradle C is resting at the casting station, positionIII, after having a casting formed thereon and is waiting to bere-engaged with the conveyor system. Cradles A, position I, and B,position II, are being transported by the conveyor and are approachingthe casting station.

As cradle B reaches position II, a pair of limit switches are actuatedwhich causes the transfer rod 10a to rapidly move both cradles B and Cin advance of the normal chain travel. Cradle C is moved to position IVwhere it is almost immediately re-engaged by the chain lugs. Cradle B ismoved to the casting forming station, position III. Six seconds arerequired to set the two cradles forward as can be seen by reference tooperation No. 1, FIG. 5.

When the cradles reach the set forward position, additional limitswitches are actuated which cause rod 10a to return to the originalposition, that shown in FIG. 4b. Two Y-shaped clamps 11a, one positionedat each end of the cradle, are raised by hydraulic motors and engagecradle stub axles 368 to clamp the cradle in position III.

Lifter head 12a is then raised by hydraulic motors 12 and passes throughthe open rectangular frame of the cradle and engages and lifts thepallet 460, pressing it against the bottom of mold box 9 as shown inFIG. 4b. The mold box is an outline of the castings to be formed. Aprons9a and 9b are flush with the top of the mold box 9 and extendhorizontally therefrom. The pallet 460 comprises the bottom of thecasting mold, the mold box forms the sides, and the top of the mold isopen.

Plastic concrete is deposited in hopper 13b and falls downward intofeeder drawer 13a. The volume of concrete in the feeder drawer 13a isprecisely that required to till the mold box 9 to the desired level.Feeder 13a is then forced outwardly across the mold box to the positionshown in FIG. 4b. As the feeder passes over the mold box, the plasticconcrete is deposited and fills the mold. The feeder immediately returnsto the initial position in register with hopper 13b where it is refilledwith plastic concrete for the next cycle. An apron 13C, which is flushwith the top of the feeder drawer, serves as a valve on the bottom ofthe hopper 13b as the feeder passes over the mold box.

As the feeder returns to its dwell position, operations Nos. 6 and 7,FIG. 5, begin simultaneously. The upper vibrator 14a is lowered into thetop of the plastic concrete in mold box 9, as shown in FIG. 4c. At thesame time the upper vibrator 14a. begins to lower, eccentric vibratorsconnected to lifter head 12a start to vibrate. The lower vibrators onlifter head 12a serve to begin settling the plastic concrete and insurethat the upper vibrator 14a' will be properly seated within the moldbox. As the upper vibrator reaches the down position it also startsvibrating,

alsaeea operation No. 8. The lower vibrator stops vibrating threeseconds after the upper vibrator starts. The upper vibrator vibrates fora total of nineteen seconds to thoroughly compact the plastic concreteinto a homogeneous mass.

When the upper vibrator stops vibrating, the lifter 12a starts down,operation No. 9. The weight of the upper Vibrator remains on the plasticcasting for one second and aids in forcing the freshly formed castingfrom the mold. Then the upper vibrators return to the up position,operation 11. When the lifter head and the upper vibrator have reachedtheir dwell positions, those shown in FIG. 4a, clamps 11a. are lowered,operation 12. The casting station remains inoperative with all elementsin the positions shown in FIG. 4a until cradle A is advanced by thenormal motion of the chain to position II. Then the cycle repeats withtransfer rod a moving cradle A into position III where a casting will beformed thereon and moving cradle B into position IV where it will bereengaged by the conveyor system and moved into the kiln.

After the cradles with the freshly formed castings thereon arere-engaged by the conveyor system, they proceed along the upper reachinto the kiln where the temperature upon entrance is maintained atapproximately 180 F. The cradles continue along the upper reach to thetake-up sprockets where the temperature rises as high as 230 F. and thenback along the lower reach to the kiln exit. The trip through the kilnrequires less than two hours depending upon the speed of the chain. Aspreviously mentioned, the humidity in the kiln is maintained as high aspossible.

' The semicured castings then cool as they proceed along the lower reachto the mat removal station, hereafter described in detail FIGS. 7-13show various detailed views of the casting station. The two transferrods 16a can be seen above the upper reach on opposite sides of thecradles in FIG. 8. Each transfer rod 10a has two legs indicatedgenerally at 10c and 10d. Referring to FIGS. 10 and 12, each lug iscomprised of a wedge 391 pivotally carried on an axle 392 which isconnected to a pair of vertical plates 392a on arm 390. Arm 390 iswelded to rod 10a. Each wedge also has an arcuate slot 394 through whicha pin 39? passes. The pin 393 is also secured to the plates 39251. Thisconstruction permits upstanding spikes 395 and 396 connected to thecradle dollies to pass under the inclined portion of the wedge 391thereby pivoting the wedge upward until the wedge drops down behind theupstanding spike so that the rod can move the cradle dollies forward.V

Each of the four transfer rod lugs are of identical construction.

A rack and pinion arrangement is provided to insure that the twotransfer rods 10a are always synchronized in movement. A rack 397 ismounted on top of each rod. A shaft (not shown) extends from one gearrack 397 transversely of the conveyor system to the other gear rackmounted on the other transfer rod. Pinions (not shown) are splined oneach end of the shaft and mesh with the gear racks 397 to insure thatmotion of one transfer rod is mechanically transmitted to the other.This arrangement insures that the movement of the rods is synchronizeddespite unequal forces which might be exerted by the two hydraulicmotors 10, shown in FIG. 13.

As previously mentioned, the transfer rods simultaneously set twocradles in advance of the chain travel. The forward cradle is re-engagedwith the chain while the rear cradle is disengaged from the chain andleft at the casting station. The chain track as it passes the castingstation is raised so that chain lugs 385 pass over the triangular cradlelugs 383 which are connected to the dollies. To insure that tension doesnot lift the chain too soon and disengage a cradle before it reachesposition II, upper rail 355b is positioned above the rollers to hold thechain As a cradle is moved from the casting station of the triangularcradle lug 387 connected to the dolly actually wedges under the chainlug 335, forcing it upwardly until the chain lug drops down behindVertical edge 383.

Several means are employed to decelerate the cradles which are movedrapidly by the transfer rods to a stop at the casting station. At eachend of the cradle, a drag brake 398 rides against plate 399 Which isconnected to the bottom of angle iron extension 386 which extendsoutwardly from each cradle dolly. The drag brake is supported by levers40d and 451 which are pivotally mounted on suitable support structure at402 and 403, respectively, and are pivotally connected to the drag brakeshoes at 404 and 405, respectively. Weights 406 and 407 are suspended atthe other ends of the levers 4d() and 401, respectively, and continuallyurge the drag brake upwardly against plate 399.

Also provided at each end of the .cradle is a spring biased detentdevice having an arm 468 which is pivotally mounted at one end 499 andis` biased outwardly by spring 414B into engagement with the leadingedge of the cradle. A cylindrical llobe 411 retains the cradle as itengages the leading edge thereof until the detent is depressed by eX-cessive force exerted on the cradle, which force occurs when thetransfer rod moves the cradle from the casting station to the point ofre-engagernent with the chain.

Y-shaped clamps 11a are provided at each end of the cradle and slide insleeves 413 when raised and lowered by hydraulic motors 11. The clampsare raised into engagement with the stub axles 36S of the cradles tohold the cradles in position at the casting forming station.

The lifter head 12a is comprised generally of a rectangular frame whichis raised and lowered by two hydraulic motors 12 supported by transversebeam 352. Four channel beams 423, 424, 425, and 426 extendlongitudinally of the lifter head and are supported in spaced relationby triangular plates 427, 423, 429, and 430. Plates 427 and 428 areinterconnected by spacer plates 431 and 432 which form a trunnion forpin 433 which is connected to rod 434 of one motor 12. Similar spacerplates and a pin pivotally .connect the piston rod 437 of the othermotor 12 to the lifter head.

Ten vibrator segments are spring supported on the rectangular lifterframe. Each vibrator section has end plates 440 and 441 and plates 442and 443 shown in FIG. 12 which are so spaced as to embrace thelongitudinal beams 423, 424, 425 in close-fitting, sliding engagement topermit independent vertical movement of each vibrator section. EachVibrator section also has cross bracing members 445, 446, 447, and 448which extend longitudinally of the lifter head and cross braces 449,45t), and 451 which extend transversely of the lifter head, and a fiat,horizontally disposed plate 452. Each vibrator section is supported bystiff coil springs 453 and 454 which are connected to channel beambraces 455. A conventional vibrator (not shown) comprised of anelectrically driven eccentric is mounted on each spring supportedvibrator section.

Each lifter head vibrator section has side lugs 456 and 45er: and acenter lug 457 projecting above the plate 452. The lifter head -is sodimensioned as to pass through the cradle between the longitudinal beams366 of the cradle and engage and lift the pallet 460 carried by thecradle. Pallet 460 is reinforced by cross braces 451 which are taperedat each end so that the pallet will align itself between the I-beams 366to a certain extent. Pallets 460 have slots (not shown) which registerand receive the lugs 456, 455g, and 457 of each vibrator section of thelifter head, so that the lugs protrude through the pallets and supportwire fabric 476 at a height above the pallet corresponding to themidpoint of the casting.

A pair of guideposts 43) and 481 which are connected to the lifter head12a are shown in FIGS. 8, 19, and 20. A wide flange 483 is rstiffened byflanges 483m and 483b

1. IN A CYCLIC MACHINE FOR PRODUCING LARGE CONCRETE MATS HAVING APLURALITY OF PALLETS ON WHICH THE MATS ARE FORMED AND CARRIED, EACHPALLET PASSING SUCCESSIVELY THROUGH STATIONS FOR PLACING REINFORCINGFABRIC THEREON, THROUGH STATIONS FOR PLACING REINFORCING FABRIC THEREON,FOR OILING THE PALLET, FOR CASTING A MAT THEREON, FOR CURING THE MAT,FOR REMOVING THE MAT THEREFROM AND FOR CLEANING THE PALLET THEIMPROVEMENT COMPRISING: (A) A PAIR OF ENDLESS CHAINS DISPOSED INPARALLEL RELATION TO EACH OTHER AND EXTENDING THROUGH SAID STATIONS; (B)MECHANISM FOR DRIVING SAID ENDLESS CHAINS SYNCHRONOUSLY WITH EACH OTHER;(C) A PLURALITY OF PALLET CARRYING CRADLES MOUNTED ON DOLLIES ANDDISENGAGEABLY CONNECTED TO SAID ENDLESS CHAINS; (D) A PAIR OF CRADLETRACKS, SAID DOLLIES RUNNING ON SAID TRACKS, SAID TRACKS GENERALLYPARALLEL TO SAID CHAINS BUT SPACED FARTHER THEREFROM ADJACENT SAID MATCASTING STATION, WHEREBY SAID CRADLES AND DOLLIES DISENGAGE FROM SAIDCHAINS ADJACENT SAID STATION; (E) RECIPROCATING TRANSFER ROD MEANS, ATTHE CASTING STATION ADJACENT SAID CRADLE TRACKS AND PARALLEL THERE-